i wouldnt say hes harrassing the cat, id say hes more protective.
yeah, since she is old and he is growling at anyone going near her, it sounds quite like protection....
Yeah getting him done should calm him down, but its sweet that he's protective of your cat. Maybe its unrequited love! But sometimes animal can sense pregnancies and illnesses and become protective...but then I gues if your cat is very old its unlikely to be pregnant.
Also.. the dog shakes.. and gets his head down like he's about to pounce almost.. if any of us go near the cat.. Mum's basically paranoid the dog will turn at any time and she doesn't want him hurting the kids..
castration calming dogs down is a myth and as often as not makes them worse, go to your vets, they will advise you, you could always invest in an indoor kennel so you can give the cat some peace
Has this suddenly started, or has your dog always been aggressive? You need to train your dog properly to recognise that he is at the bottom of the family social structure and then he will always defer to you.
This is a recent thing.
He even went to get groomed the other day and she said for the first time ever (he's been going for years) that she had to muzzle him up.
He listens to mum, but he's starting to look like he's going to go for her now too.. And it's all over the friggin' cat!